ocfs2: check if the ocfs2 lock resource has been initialized before calling ocfs2_dlm_lock
If ocfs2 lockres has not been initialized before calling ocfs2_dlm_lock,
the lock won't be dropped and then will lead umount hung. The case is
described below:
ocfs2_mknod
ocfs2_mknod_locked
__ocfs2_mknod_locked
ocfs2_journal_access_di
Failed because of -ENOMEM or other reasons, the inode lockres
has not been initialized yet.
iput(inode)
ocfs2_evict_inode
ocfs2_delete_inode
ocfs2_inode_lock
ocfs2_inode_lock_full_nested
__ocfs2_cluster_lock
Succeeds and allocates a new dlm lockres.
ocfs2_clear_inode
ocfs2_open_unlock
ocfs2_drop_inode_locks
ocfs2_drop_lock
Since lockres has not been initialized, the lock
can't be dropped and the lockres can't be
migrated, thus umount will hang forever.
Signed-off-by: Alex Chen <alex.chen@huawei.com> Reviewed-by: Joseph Qi <joseph.qi@huawei.com> Reviewed-by: joyce.xue <xuejiufei@huawei.com> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>